Trimming apparatus and method for fuel cell membrane/electrode coupling and transporting apparatus

ABSTRACT

A membrane/electrode assembly trimming apparatus ( 10 ) made up of a lower trimming die ( 14 ) on which a membrane/electrode assembly ( 65 ) is set, an upper trimming die ( 16 ) having a trimming blade ( 15 ) and a pressing member ( 17 ) which is ascend/descendably suspended from this upper trimming die and suction-holds a carbon electrode ( 12 ). A membrane/electrode assembly carrying apparatus ( 72 ) including a pressing member which suction-grips a carbon electrode and prevents it from slipping sideways is also disclosed. Because the certainty of the positioning, fixing and trimming of the membrane/electrode assembly at the time of trimming is raised and positional slipping of the trimmed membrane/electrode assembly during carrying can be prevented, the performance of the fuel cell improves.

TECHNICAL FIELD

This invention relates generally to the manufacture of a fuel cell andparticularly to a fuel cell membrane/electrode assembly trimming systemin which a fuel cell membrane/electrode assembly is positioned and fixedcertainly for trimming and positional deviation during carrying of thefuel cell membrane/electrode assembly after trimming is prevented, andto a fuel cell membrane/electrode assembly carrying apparatus with whicha trimming step and a carrying step are made to connect smoothly and atransition from the carrying step to a stacking step is made smooth.

BACKGROUND ART

A fuel cell is a cell which utilizes the opposite principle to theelectrolysis of water to obtain electricity in the process of obtainingwater by causing a reaction between hydrogen and oxygen. Becausegenerally a fuel gas is substituted for hydrogen and air or an oxidantgas is substituted for oxygen, the terms fuel gas, air and oxidant gasare often used.

As this kind of fuel cell, for example the “fuel cell” inJP-A-2000-123848 is known. The cell of this fuel cell is constructed asshown in FIG. 11.

As shown in FIG. 11, a cell 100 is made by affixing an anode sideelectrode 102 and a cathode side electrode 103 to both sides of anelectrolyte membrane 101 and sandwiching the anode side electrode 102and the cathode side electrode 103 with two separators 104, 105.Multiple flow grooves 106 for supplying hydrogen gas, which is a fuel,to the anode side electrode 102 are formed in the separator 104, andmultiple flow grooves 107 for supplying oxygen gas, which is an oxidantgas, to the cathode side electrode 103 are formed in the separator 105.A required voltage is obtained by stacking numerous cells 100constructed like this.

The reference numerals 111, 112 denote seals (gaskets) for sealing thegaps between the electrolyte membrane 101 and the separators 104, 105.

The electrolyte membrane 101 is a polymer electrolyte membrane (PEM:Polymer Electrolyte Membrane) made of a polymer compound. Thiselectrolyte membrane 101 will hereinafter be written PEM 101.

And, the PEM 101, the anode side electrode 102 and the cathode sideelectrode 103 constitute a membrane/electrode assembly (MEA: MembraneElectrode Assembly) 108. This membrane/electrode assembly 108 willhereinafter be written MEA 108.

In the above-mentioned Japanese patent publication there is nodescription of a manufacturing method and a carrying method of the MEA108, but generally a method is known wherein [1] to the front and rearsides of a PEM cut larger than the shape to which it is to be finallyshaped an anode side electrode 102 and a cathode side electrode 103 witha smaller area than this PEM are press-affixed; [2] the edge of the PEMis finally shaped by cutting (trimming) with a trimming blade; and [3]the trimmed membrane-form MEA 108 is suction-gripped with asuction-gripping device while being carried to the next step.

The present inventors tried this manufacturing and carrying, but in thetrimming (final shaping) step [2] and the carrying step [3] the kinds ofproblem shown in FIG. 12A to FIG. 12C arose.

FIG. 12A to FIG. 12C are explanatory views illustrating an MEA trimmingstep and a carrying step which follows this trimming step: FIG. 12A is asectional view showing the trimming process; FIG. 12B is a sectionalview showing a suction-gripping operation; and FIG. 12C is a sectionalview showing a carrying operation.

In FIG. 12A, with a PEM 101 a with electrodes 102, 103 affixed to itplaced on a table 121 and positioned by positioning means not shown inthe figure, a press apparatus 123 fitted with a trimming blade 122 islowered as shown by the white arrow and the PEM 101 a is trimmed. Todistinguish it from the post-trimming PEM 101, the pre-trimming PEM isdenoted with the reference numeral 101 a.

In FIG. 12B, after trimming of the PEM 101 is finished, asuction-gripping apparatus 124 separate from the press apparatus 123(see FIG. 12A) is lowered as shown by the white arrow and suction-gripsthe MEA 108.

In FIG. 12C, the MEA 108 suction-gripped by the suction-grippingapparatus 124 is lifted as shown by the white arrow d and carried to asubsequent stacking step as shown by the white arrow e.

In FIG. 12B, because the press apparatus 123 shown in FIG. 12A and thesuction-gripping apparatus 124 shown in FIG. 12B are interchanged on thetable 121 before the suction-gripping operation is carried out, the flowtemporarily stops at the time of the transition from the trimmingprocess to the suction-gripping process. Consequently, when trimming andcarrying of the MEA 108 are carried out continuously on a productionline, productivity can be expected to fall greatly.

The MEA 108, having had its edges trimmed to a predetermined size, afterthis edge-trimming, is carried from a trimming station, where theedge-trimming is carried out, to a stacking station, to be stacked witha separator. In FIG. 12A and FIG. 12B, from when the PEM 101 a istrimmed by the press apparatus 123 to when it is suction-gripped by thesuction-gripping apparatus 124, for example, if the position of the MEA108 slips, the MEA 108 is carried by the suction-gripping apparatus 124with its position still slipped, and in the stacking step, the positionof the MEA 108 must be corrected. As a result, the manufacturing laborof the fuel cell may increase and the productivity of the fuel cell mayfall.

Also, a separate problem of the kind shown in FIG. 13A and FIG. 13Barose.

FIG. 13A and FIG. 13B are explanatory views illustrating an MEA trimmingapparatus and trimming process: FIG. 13A is a sectional view showingbefore the trimming process, and FIG. 13B is a sectional view showingafter the trimming process.

In FIG. 13A, first, a PEM 101 a (to distinguish it from thepost-trimming PEM 101, the reference numeral of the pre-trimming PEMwill for convenience be made 101 a) with electrodes 102, 103 affixed toits sides is placed on a table 131, and the edges of the PEM 101 a arefixed to the table 131 with for example clamping members 132.

Then, from above the PEM 101 a , a press apparatus 123 fitted with atrimming blade 122 is lowered as shown with arrows, and the PEM 101 a istrimmed by the trimming blade 122.

When the above-mentioned clamping members 132 are used to fix the PEM101 a, when the clamping members 132 are tightened, it sometimes happensthat a clamping member 132 moves and makes a crease in the PEM 101 a,which is a film-like workpiece, or that clamping members 132 pull on thePEM 101 a against each other and stretch the PEM 101 a, and the qualityof the PEM 101 a is impaired.

And, also when the PEM 101 a is positioned on the table 131, because itis a film-like workpiece, a method must be used such that it is notdamaged.

Also, when metal ions attach to the electrodes 102, 103, these metalions bond with electrons and metal separates at the carbon electrode. Itsometimes happens that because of this, separated metal hinders thereaction between the hydrogen and the oxygen and lowers the performanceof the fuel cell, and to improve the performance of the fuel cell it isdesirable for the attachment of metal ions to the electrodes 102, 103 tobe prevented.

In FIG. 13B, when trimming is finished, the press apparatus 123 israised as shown with arrows.

It sometimes happens that the MEA 108 made up of the PEM 101 and theelectrodes 102, 103, of which trimming is finished, has slipped sidewaysas shown with a white arrow, and if sideways slipping occurs beforetrimming is completed, the accuracy of the trimming becomes poor and thequality of the fuel cell is impaired.

Also, the kinds of problem shown in FIG. 14A, FIG. 14B, FIG. 15A andFIG. 15B occurred.

FIG. 14A and FIG. 14B are explanatory views illustrating an MEA trimmingapparatus and a trimming blade shape, which has an influence on thetrimming process of this trimming apparatus: FIG. 14A is a sectionalview showing before the trimming process and FIG. 14B is a sectionalview showing trimming in progress.

In FIG. 14A, a PEM 101 a having electrodes affixed to its sides isplaced on a table 131. Next, from above the PEM 101 a, a trimming blade122 in the blade edge 122 a of which undulations have arisen is loweredas shown with a white arrow. (For the purposes of illustration, thedegree of undulation in the blade edge 122 a has been exaggerated.)

In FIG. 14B, the PEM 101 a is trimmed with the trimming blade 122.However, because of the undulations in the blade edge 122 a, of thecross-section of the PEM 101 a, the parts shown with cross-hatching arenot trimmed.

To trim the PEM 101 a completely, the trimming blade 122 must be pushedagainst the PEM 101 a with a still larger pushing force, and because theload acting on the trimming blade 122 becomes large, it is necessary toincrease the strength of the trimming blade 122 to withstand this loadand to make the cylinder apparatus for pushing the trimming blade 122large.

FIG. 15A and FIG. 15B are explanatory views illustrating an MEA trimmingapparatus and a trimming blade inclination, which has an influence onthe trimming process of this trimming apparatus: FIG. 15A is a sectionalview showing before the trimming process, and FIG. 15B is a sectionalview showing trimming in progress.

In FIG. 15A, a PEM 101 with electrodes affixed to its sides is placed ona table 131.

From above the PEM 101 a a trimming blade 135 is lowered as shown with awhite arrow.

For example, when the parallelness of the upper face of the table 131and the blade edge 136 of the trimming blade 135 is large (the bladeedge 136 is inclined at an angle θ to the upper face of the table 131),in FIG. 15B, when the PEM 101 a is trimmed with the trimming blade 135,of the cross-section of the PEM 101 a , the part shown withcross-hatching is not trimmed.

Consequently, to trim the PEM 101 a, in the same way as that explainedwith reference to FIG. 14A and FIG. 14B, it is necessary to apply astill larger pushing force to the trimming blade 135.

DISCLOSURE OF THE INVENTION

The present invention, in a first aspect, provides a fuel cellmembrane/electrode assembly trimming apparatus for, with amembrane/electrode assembly made by affixing to both sides of a polymerelectrolyte membrane carbon electrodes of smaller area than this as theobject of trimming, trimming with a trimming blade the edge of thepolymer electrolyte membrane, including a lower trimming die on which amembrane/electrode assembly is set and an upper trimming die having atrimming blade and a pressing member ascend/descendably suspended fromthis upper trimming die, wherein the pressing member is provided withsuction-gripping means for suction-gripping and holding one of thecarbon electrodes.

By the upper trimming die being integrally provided with a trimmingblade and suction-gripping means provided on a pressing member, trimmingwith the trimming blade can be carried out with the polymer electrolytemembrane pressed down with the pressing member and a carbon electrodesuction-gripped by the suction-gripping means, and consequently pressingdown and cutting of the polymer electrolyte membrane andsuction-gripping of the carbon electrode can be carried out smoothly andswiftly in a single series of operations. Therefore, the productivity ofthe fuel cell can be raised.

Preferably, the pressing member is provided with a pressing part forpressing down the edge of the polymer electrolyte membrane and a recessfor receiving one of the carbon electrodes; an electrode suction holefor suctioning the carbon electrode is provided in the bottom face ofthis recess; and a membrane suction hole for suctioning the polymerelectrolyte membrane is provided in the pressing part. During trimmingof the polymer electrolyte membrane, by pressing down the edge of thepolymer electrolyte membrane with the pressing part and suctioning thecarbon electrode with the electrode suction hole and suctioning thepolymer electrolyte membrane with the membrane suction hole, it ispossible to prevent sideways slipping of the membrane/electrode assemblyand hold the membrane/electrode assembly certainly.

The mechanism for suspending the pressing member on the upper trimmingdie is preferably made up of guide rods extending between the twomembers and elastic members urging the pressing member toward the lowertrimming die. Because the mechanism for suspending the pressing memberfrom the upper trimming die has guide rods, the pressing member can beraised and lowered with respect to the upper trimming die with goodprecision.

It is desirable for a porous plate to be fitted to the bottom face ofthe recess and for the carbon electrode to be suction-gripped using thisporous plate. Air inside the recess can be sucked through the porousplate, and compared to a case wherein the carbon electrode issuction-gripped locally with a suction-gripping device, the carbonelectrode can be suction-gripped with a substantially uniformsuction-gripping force over the whole surface of the porous plate bymeans of holes distributed over the whole of the porous plate, and thereis no damaging of the carbon electrode. Because it is a porous plate,the frictional force between the porous plate and the carbon electrodeof when the carbon electrode is suction-gripped can be made large, andthe effect preventing sideways slipping of the carbon electrode can beraised still further.

It is desirable, by providing a first bearing member of a larger areathan the membrane/electrode assembly on the lower trimming die and asecond bearing member for bearing the edge of the polymer electrolytemembrane on this first bearing member, to adopt a structure such thatthe cutting force of the trimming blade is transmitted in the order ofthe edge of the polymer electrolyte membrane, the second bearing member,the first bearing member. If a structure is adopted such that thecutting force of the trimming blade is born by a first bearing memberand a second bearing member, for example, the material properties of thefirst bearing member and the second bearing member can be madedifferent. If a difference in hardness is made between the first bearingmember and the second bearing member, then when the polymer electrolytemembrane is trimmed with the trimming blade, by deforming the firstbearing member or the second bearing member so as to follow the shape ofthe blade edge of the trimming blade, it is possible to absorb assemblyerrors of the lower trimming die and the upper trimming die and error ofassembly of the trimming blade with respect to the upper trimming diewith the first bearing member and the second bearing member.

That is, if the first bearing member or the second bearing member ismade relatively hard, relatively small deviations such as dimensionalerror of the trimming blade itself can be absorbed while the cuttingforce is certainly transmitted to the polymer electrolyte membrane. Ifthe first bearing member or the second bearing member is made soft,large deviations such as assembly errors of the lower trimming die andthe upper trimming die and assembly error of the trimming blade withrespect to the lower trimming die can be absorbed. Accordingly, forexample by combining the different first bearing member and secondbearing member which are different in hardness it is possible to absorbdimensional errors and assembly errors of the aforementioned parts andabut the whole of the trimming blade with the polymer electrolytemembrane, and also it is possible to transmit the cutting force of thetrimming blade certainly to the polymer electrolyte membrane, the secondbearing member and the first bearing member. Therefore, trimming of thepolymer electrolyte membrane can be carried out certainly with a smallload.

The first bearing member is preferably made as an elastic body. If thefirst bearing member is an elastic body, then even when the parallelnessof the blade edge of the trimming blade and the lower trimming die sidehas become large, when the edge of the polymer electrolyte membrane istrimmed with the trimming blade, the first bearing member distorts andthe whole of the trimming blade can abut with the polymer electrolytemembrane, and the polymer electrolyte membrane can be cut with the wholeof the trimming blade uniformly.

The second bearing member can be made a soft material harder than thefirst bearing member. If the second bearing member is made a softmaterial, then even when undulations have arisen in the blade edge ofthe trimming blade and the blade edge is not straight, when the edge ofthe polymer electrolyte membrane is trimmed with the trimming blade, thetrimming blade can bite into the second bearing member, the whole of thetrimming blade abuts with the polymer electrolyte membrane, and thepolymer electrolyte membrane can be cut uniformly with the whole of thetrimming blade.

In a second aspect, the invention provides a fuel cellmembrane/electrode assembly trimming method for, with amembrane/electrode assembly made by affixing to both sides of a polymerelectrolyte membrane carbon electrodes of smaller area than this as theobject of trimming, trimming with a trimming blade the edge of thepolymer electrolyte membrane, wherein a recess with its bottom face madeof a nonmetallic plate is provided in the lower trimming die, and aftera carbon electrode is received in this recess and positioning of thiscarbon electrode is effected with two adjacent side walls of the recess,the edge of the polymer electrolyte membrane is suction-gripped to thelower trimming die and the polymer electrolyte membrane is trimmed withthe trimming blade.

By fixing the edge of the polymer electrolyte membrane bysuction-gripping it to the lower trimming die, there is no risk of thepolymer electrolyte membrane, which is a film-like workpiece, beingdamaged in the trimming of the edge of the polymer electrolyte membrane,and the quality of the membrane/electrode assembly can be improved. Bypositioning of the carbon electrode being carried out by two adjacentside walls of the recess, positioning can be carried out withoutdamaging the polymer electrolyte membrane and the carbon electrode.Also, by receiving the carbon electrode in a recess having its bottomface constituted by a nonmetallic plate, there is no risk of metal ionsattaching to the carbon electrode and the performance of the fuel cellcan be improved.

Preferably, the suction-gripping of the polymer electrolyte membrane iscarried out on the part which becomes unneeded after trimming of thepolymer electrolyte membrane. If after trimming the necessary part ofthe polymer electrolyte membrane is moved from the lower trimming die toelsewhere, it is possible for only the part of the polymer electrolytemembrane which has become unnecessary to be left on the lower trimmingdie, and if the suction-gripping of the unnecessary part is stopped, thework of removing the unnecessary part from the lower trimming die can becarried out efficiently.

In a third aspect, the invention provides a fuel cell membrane/electrodeassembly trimming apparatus wherein edge-trimming of amembrane/electrode assembly, made by affixing to both sides of a polymerelectrolyte membrane carbon electrodes of smaller area that this, iscarried out at a trimming station. For stacking of this edge-trimmedmembrane/electrode assembly, the membrane/electrode assembly is carriedfrom the trimming station to a stacking station, including a sliderwhich moves from the trimming station to the stacking station, an armextending from this slider, an upper trimming die that is suspended fromthis arm and has a trimming blade for the trimming, arm moving means formoving the arm, and a pressing member attached to the upper trimming diefor suction-gripping one of the carbon electrodes and holding it so thatit does not slip sideways.

If a structure is adopted wherein a pressing member for suction-grippingand holding a carbon electrode is mounted to an upper trimming die foredge-trimming a membrane/electrode assembly and the membrane/electrodeassembly is suction-gripped with the pressing member from the time oftrimming to the time of carrying, the membrane/electrode assembly can becarried from a trimming station to a stacking station still in its stateof the time of trimming, without it slipping sideways. As a result, whenthe membrane/electrode assembly is stacked with a separator at thestacking station, deviation of the stacking position of themembrane/electrode assembly can be prevented. Consequently, when themembrane/electrode assembly is stacked, it is not necessary for theposition of the membrane/electrode assembly to be corrected, and asmooth transition can be made from the carrying step to the stackingstep.

The arm moving means preferably includes a vertical movement mechanismfor moving the arm in the vertical direction and a horizontal movementmechanism for moving the arm horizontally and in a straight line. If avertical movement mechanism and a horizontal movement mechanism areprovided, the movement of the arm becomes rectilinear movement in eachof two directions, the vertical direction and a horizontal direction;the movement distance of the arm becomes short; and the carrying timecan be shortened. Accordingly, the productivity of the fuel cell can beimproved. By making the horizontal movement rectilinear, compared to amechanism wherein the horizontal movement is for example planar, the armmoving means can be made a simple structure. Also, because the movementdirection is two directions, the force acting on the membrane/electrodeassembly can be made a fixed direction at all times; it can be madedifficult for shocks to act on the membrane/electrode assembly beingcarried; and sideways slipping of the membrane/electrode assembly incarriage can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a fuel cell membrane/electrode assemblytrimming apparatus according to the invention;

FIG. 2 is a flowchart of manufacturing of a fuel cell including atrimming process carried out by an MEA trimming apparatus according tothe invention;

FIG. 3A to FIG. 3C are views illustrating positioning of a PEM on an MEAtrimming apparatus according to the invention, FIG. 3A and FIG. 3B beingplan views and FIG. 3C being a sectional view on the line c—c in FIG.3B;

FIG. 4A and FIG. 4B are views illustrating a PEM trimming processcarried out by an MEA trimming apparatus according to the invention,FIG. 4A being a sectional view showing a trimming process and FIG. 4B asectional view showing a suction-gripping operation;

FIG. 5 is a view illustrating a PEM trimming position of an MEA trimmingapparatus according to the invention;

FIG. 6 is a view illustrating a trimming process in which considerationhas been given to the trimming blade shape of an MEA trimming apparatusaccording to the invention;

FIG. 7A and FIG. 7B are action views illustrating the action of atrimming process in which consideration has been given to theinclination of the trimming blade of an MEA trimming apparatus accordingto the invention, FIG. 7A being a sectional view showing before thetrimming process and FIG. 7B a sectional view showing the trimmingprocess;

FIG. 8 is a front view of a fuel cell manufacturing apparatus having aMEA trimming apparatus and an MEA carrying apparatus according to theinvention;

FIG. 9 is a plan view of a fuel cell manufacturing apparatus having anMEA trimming apparatus and an MEA carrying apparatus according to theinvention;

FIG. 10 is a view illustrating the operation of an MEA carryingapparatus according to the invention;

FIG. 11 is a sectional view of a cell of a fuel cell battery;

FIG. 12A to FIG. 12C are explanatory views illustrating an MEA trimmingstep and a carrying step which follows this MEA trimming step, FIG. 12Abeing a sectional view showing a trimming process, FIG. 12B a sectionalview showing a suction-gripping operation and FIG. 12C a sectional viewshowing a carrying operation;

FIG. 13A and FIG. 13B are explanatory views illustrating an MEA trimmingapparatus-and trimming process, FIG. 13A being a sectional view showingbefore the trimming process and FIG. 13B a sectional view showing afterthe trimming process;

FIG. 14A and FIG. 14B are views illustrating an MEA trimming apparatusand a trimming blade shape, which influences the trimming processcarried out by this trimming apparatus, FIG. 14A being a sectional viewshowing before the trimming process and FIG. 14B a sectional viewshowing after the trimming process;

FIG. 15A and FIG. 15B are explanatory views illustrating an MEA trimmingapparatus and a trimming blade inclination, which influences thetrimming process carried out by this trimming apparatus, FIG. 15A beinga sectional view showing before the trimming process and FIG. 15B asectional view showing after the trimming process;

BEST MODES FOR CARRYING OUT THE INVENTION

As shown in FIG. 1, a membrane/electrode assembly trimming apparatus 10(hereinafter written “MEA trimming apparatus 10”) constituting atrimming station is made up of a lower trimming die 14, on which isplaced a polymer electrolyte membrane 13 a (hereinafter written “PEM 13a”; the pre-trimming PEM will be written PEM 13 a like this todistinguish it from a post-trimming PEM 13, which will be furtherdiscussed later) having carbon electrodes 11, 12 made of carbon paperpress-affixed to both its sides; an upper trimming die 16, having atrimming blade 15 for cutting off the edges of, i.e. trimming, the PEM13 a; a suction-gripping/holding device 17 serving as a pressing memberconnected to the upper trimming die 16 for suction-gripping and holdingthe carbon electrode 12 and the PEM 13 a, and a cylinder device 18 forlowering the upper trimming die 16.

The lower trimming die 14 is made up of a table part 21, which doublesas a part for positioning the PEM 13 a; a lower die support part 22,which supports this table part 21; and a lower die suction-gripping part23, which suction-grips the periphery of the PEM 13 a.

The table part 21 is made up of a lower bearing member 25, serving as afirst bearing part provided on a bottom part 22 a of the lower diesupport part 22, and an upper bearing member 26, serving as a secondbearing member disposed on top of this lower bearing member 25, on whichthe PEM 13 a is placed. A positioning receiving part 27 constituting arecess for positioning the carbon electrode 11 is provided in the middleof the upper bearing member 26, and a resin plate 28 serving as anonmetallic plate is disposed in the top of the lower bearing member 25and below the positioning receiving part 27.

The lower bearing member 25 is made of a foam-form elastic material suchas polyurethane, and the upper bearing member 26 is made of a softmaterial such as PET (polyethylene terephthalate). The resin plate 28 isa member for preventing the carbon electrode 11 from making contact withthe lower bearing member 25, so that when metal ions are attached to thelower bearing member 25 the metal ions do not attach to the carbonelectrode 11.

If metal ions attach to the carbon electrode 11, these metal ionscombine with electrons and metal separates at the carbon electrode 11.It sometimes happens that because of this, separated metal hinders thereaction between the hydrogen and the oxygen and lowers the performanceof the fuel cell.

The lower die suction-gripping part 23 is made up of suction openings 31provided in the table part 21 and connecting pipes 33 severallyconnected to these suction openings 31 by way of joints 32, and byconnecting these connecting pipes 33 to an aspirator not shown in thefigures, air is drawn through the suction openings 31 and the PEM 13 ais suction-gripped.

The trimming blade 15 is approximately rectangular in plan view and is amember for cutting off the edge of the PEM 13 a on the outside of thecarbon electrodes 11, 12.

The upper trimming die 16 is made up of the trimming blade 15 and atrimming blade mounting part 35 to which this trimming blade 15 ismounted.

The suction-gripping/holding device 17, to press down upon and positionthe PEM 13 a for trimming of the PEM 13 a and prevent sideways slippingof the PEM 13 a during carrying after trimming, is connected to thetrimming blade mounting part 35 by rods 36 serving as guide rods and ispressed downward by springs 37 serving as elastic members interposedbetween itself and the trimming blade mounting part 35, and is made upof a pressing part 41 for pressing down upon the PEM 13 a duringtrimming, a first recess part 42 provided inward of this pressing part41, a pad 43 serving as a porous plate made of a porous materialdisposed inside this first recess part 42, a first upper diesuction-gripping part 44 serving as suction-gripping means forsuction-gripping the carbon electrode 12 by way of this pad 43, andsecond upper die suction-gripping parts 45 for suction-gripping the PEM13 a at the position of the pressing part 41. 17 a denotes guide holesprovided in the trimming blade mounting part 35 for guiding the rods 36;17 b denotes through holes for connecting pipes 48, 52 to pass through;and 43 a is a second recess provided in the lower part of the pad 43 forreceiving the carbon electrode 12.

The pad 43 is made of a porous resin material and has gas permeability,and moreover is also for preventing metal ions from attaching to thecarbon electrode 12, like the resin plate 28 of the lower trimming die14 described above.

The first upper die suction-gripping part 44 is made up of asuction-gripping hole 47 serving as an electrode suction hole providedin the bottom of the first recess part 42 and a connecting part 48connected to this suction hole 47 by a joint 32, and by connecting thisconnecting part 48 to an aspirator not shown in the figures air insidethe first recess part 42 is drawn through the pad 43 and thesuction-gripping hole 47 to suction-grip the carbon electrode 12.

The second upper die suction-gripping part 45 is made up ofsuction-gripping holes 51 serving as membrane suction holes provided inthe pressing part 41 and connecting pipes 52 severally connected tothese suction-gripping holes 51 by way of joints 32, and by connectingthese connecting pipes 52 to an aspirator not shown in the figures airis drawn through the suction-gripping holes 51 to suction-grip the PEM13.

The cylinder device 18 is made up of a cylinder proper 61; a piston, notshown in the figure, movably received in this cylinder proper 61; apiston rod 62 attached to this piston; and a pressing part 63 attachedto the lower end of this piston rod 62.

The main points of the manufacture of a fuel cell including an MEAtrimming process carried out by the MEA trimming apparatus 10 describedabove will be described next.

Next, a flow of manufacture of a fuel cell battery cell including atrimming process carried out by an MEA trimming apparatus according tothe invention will be described, with reference to FIG. 2. STxx meansStep.

ST01: A PEM with carbon electrodes affixed to it is set on a lowertrimming die.

ST02: The PEM is positioned.

ST03: The PEM is trimmed to make an MEA.

ST04: The MEA is carried to a stacking station.

ST05: A sealing material is applied to separators.

ST06: The separators with the sealing material applied and the MEA arestacked to make a cell. By stacking multiple cells like this, a fuelcell battery with a required voltage is obtained.

The above-mentioned steps ST01 to ST03 will now be described in detail,with reference to FIG. 3A to FIG. 3C.

First, in FIG. 3A, a PEM 13 a with carbon electrodes 11, 12 (the carbonelectrode 11 is on the back side of the PEM 13 a) affixed to it isplaced on the table part 21 of the lower trimming die 14.

In FIG. 3B and FIG. 3C, two sides of the carbon electrode 11 are abuttedwith two side walls 27 a, 27 b of the positioning receiving part 27 ofthe table part 21 to effect positioning of the carbon electrode 11 withrespect to the table part 21, that is, positioning of the PEM 13 a withrespect to the table part 21. (In FIG. 3B, for convenience ofdescription, the carbon electrode 12 is not shown.)

By positioning of the carbon electrode 11 being effected with twoadjacent side walls 27 a, 27 b of the positioning receiving part 27 likethis, positioning can be carried out without damaging the PEM 13 a andthe carbon electrode 11 and simply and furthermore exactly.

Next, the operation of the PEM trimming process carried out by an MEAtrimming apparatus according to the invention will be described, withreference to FIG. 4A and FIG. 4B.

After positioning of the PEM 13 a with respect to the table part 21 iscarried out as shown in FIG. 3, suction-gripping of the periphery of thePEM 13 a by the lower die suction-gripping part 23 shown in FIG. 1 isstarted, and in this suction-gripping state the cylinder device 18 isoperated and from the state of FIG. 1 the pressing part 63 of thecylinder device 18 is lowered as shown in FIG. 4A and the trimming blademounting part 35 of the upper trimming die 16 is pressed downward.

As a result of this, the carbon electrode 12 is received in the secondrecess 43 a, the PEM 13 a is pressed down with the elastic force of thesprings 37 by the pressing part 41 of the suction-gripping/holdingdevice 17, and after this the edge of the PEM 13 a is trimmed by thetrimming blade 15.

Here, the MEA before the edge is trimmed will be written MEA 65 a (seeFIG. 4A), and the assembly of the PEM 13 with its edge trimmed and thecarbon electrodes 11, 12 will be called the membrane/electrode assembly65, or MEA 65.

During trimming and after trimming of the edge of the PEM 13 a, thecarbon electrode 12 is suction-gripped by the first upper diesuction-gripping part 44 and the PEM 13 a is suction-gripped by thesecond upper die suction-gripping parts 45.

At this time, when the carbon electrode 12 is suction-gripped by thefirst upper die suction-gripping part 44 by way of the pad 43, a forcedue to the suction shown by the arrow N (this force will be called theforce N) acts on the upper face of the carbon electrode 12, and when inthis state the carbon electrode 12 tends to slip sideways over thesurface of the pad 43, between the carbon electrode 12 and the pad 43 africtional force F1 or a frictional force F2 shown by the arrow F1 orthe arrow F2 arises due to the force N.

That is, a frictional force arises in the opposite direction to themovement direction of the carbon electrode 12, so that if the carbonelectrode 12 tends to slip sideways to the right with respect to the pad43 a frictional force F1 arises, and if the carbon electrode 12 tends toslip sideways to the left a frictional force F2 arises.

In this way, by the frictional force F1 or the frictional force F2described above, sideways slipping of the carbon electrode 12 and hencethe MEA 65 a during trimming can be prevented. Thus the trimmingprecision can be raised, and the quality of the fuel cell can beimproved.

After the trimming of the edge of the PEM 13 a, as shown in FIG. 4B, thepressing part 63 of the cylinder device 18 is raised and the uppertrimming die 16 is thereby raised. At the first upper diesuction-gripping part 44 and the second upper die suction-gripping parts45, suction-gripping for carrying the carbon electrodes 11, 12 and thePEM 13 continues, and they are carried to a stacking station (notshown).

As shown in the above-mentioned FIG. 4A and FIG. 4B, if sidewaysslipping of the MEA 65 a can be prevented in the MEA trimming apparatus10, then when the MEA 65 is carried from this trimming step to the nextstep, for example a stacking step in which the MEA 65 is stacked withseparators, until the stacking station, which is a predetermineddistance away from the MEA trimming apparatus 10, by controlling it tomove over that distance with good precision, positioning of the MEA 65at the stacking station can be carried out with good accuracy evenwithout positioning being carried out especially at the stackingstation.

The frame-shaped piece 13 b cut from the PEM 13 and become unneeded isremoved from the lower trimming die 14 after suction-gripping by thelower die suction-gripping part 23 is stopped.

In related art, because suction-gripping of the frame-shaped piece 13 bhas not been carried out, it has happened that when the MEA 65 is movedfrom the lower trimming die 14, the frame-shaped piece 13 b movestogether with the MEA 65 or scatters to positions away from the lowertrimming die 14, and its removal has consequently been troublesome. Inthis embodiment, by suction-gripping the frame-shaped piece 13 b, theframe-shaped piece 13 b can be held in a fixed location at all times,and if the suction-gripping of the PEM 13 a is stopped, the operation ofremoving the frame-shaped piece 13 b from the lower trimming die 14 canbe carried out efficiently.

In FIG. 5, the PEM 13 a is trimmed with the trimming blade 15 of FIG. 4Aat the position shown with a broken line 67. This trimming position is apart on the outer side of the profile of the carbon electrodes 11, 12(the carbon electrode 11 on the back side is not shown in the figure).

In FIG. 6, when the edge of the PEM 13 a is trimmed, even if for exampleundulations have formed in the blade edge 15 a of the trimming blade 15,because the upper bearing member 26 of the lower trimming die 14 is madeof a soft material, the blade edge 15 a of the trimming blade 15 bitesinto the upper bearing member 26, and the uppermost part of theundulations of the blade edge 15 a, for example point A, can be broughtto below the underside of the PEM 13 a, and the PEM 13 a can be cut withthe whole of the blade edge 15 a. Therefore, the PEM 13 a can be trimmedcertainly even with a relatively light load.

In FIG. 7A, for example when the blade edge 15 a of the trimming blade15 of the upper trimming die 16 is inclined by an angle θ to the upperface of the table part 21 of the lower trimming die 14 (the upper faceof the upper bearing member 26) and the blade edge 15 a is straight,that is, when the parallelness of the table part 21 and the blade edge15 a of the trimming blade 15 is large, as shown in FIG. 7B, when thePEM 13 a is trimmed, the compression of the lower bearing member 25,which is an elastic body, locally becomes large, and the respectiveupper faces of the upper bearing member 26 and the PEM 13 a follow theblade edge 15 a of the trimming blade 15, and the blade edge 15 a abutswith the whole face of the PEM 13 a. Consequently, the PEM 13 a can betrimmed certainly with a small load.

Because a large load does not act on the trimming blade 15, as is clearfrom FIG. 6, FIG. 7A and FIG. 7B, friction on the trimming blade 15 canbe suppressed. Because the strength of the various components of the MEAtrimming apparatus 10 (see FIG. 1) only needs to be small, and there isno need for the cylinder device 18 (see FIG. 1) for pushing down thetrimming blade 15 to be made large, the manufacturing cost of the MEAtrimming apparatus 10 can be reduced.

As shown in FIG. 8, a fuel cell manufacturing apparatus 70 is made up ofan MEA trimming apparatus 71 constituting a trimming station, an MEAcarrying apparatus 72, a stacking part 73 constituting a stackingstation, and a base part 74 on which these are set. The MEA trimmingapparatus 71 is different from the MEA trimming apparatus 10 shown inFIG. 1 in a part of its construction, but its basic structure is thesame, and the same parts have been given the same reference numerals anda detailed description of them will be omitted.

The MEA trimming apparatus 71 is made up of a lower trimming die 14, anupper trimming die 16, a suction-gripping/holding device 17 serving assuction-gripping/holding means, and a cylinder device 76 for loweringthe upper trimming die 16.

The cylinder device 76 is made up of a cylinder proper 61, a piston notshown in the figure, a piston rod 62, and a pressing part 77 attached tothe lower end of this piston rod 62.

The upper trimming die 16 floats on the suction-gripping/holding device17 by way of rods 36 and springs 37.

The MEA carrying apparatus 72 is made up of a slider 78 serving as ahorizontal movement mechanism for moving from the position of the MEAtrimming apparatus 71 to the stacking part 73; arms 81, 81 attached tothis slider 78 by a post 79; and an arm raising/lowering motor 82 forraising and lowering these arms 81, 81.

The stacking part 73 has a stacking table 93, which is a table forstacking a separator 91 and an MEA 65 upon, and is provided with apositioning part, not shown in the figure, for positioning a separator91 on this stacking table 93.

The slider 78 is made up of a rail part 84 laid on a base 74; a movingbody 85 which moves on this rail part 84; and a horizontal drive motor86, which constitutes a drive source of this moving body 85.

The arms 81 suspend the upper trimming die 16 by way of thesuction-gripping/holding device 17.

The arm raising/lowering motor 82 is mounted on an upper rear part ofthe post 79.

The post 79, the arms 81 and the arm raising/lowering motor 82constitute a vertical movement mechanism 87.

And, the arm raising/lowering motor 82 and the horizontal drive motor 86constitute arm moving means 88.

Referring to FIG. 9, the arm raising/lowering motor 82 is mounted on theback of the post 79, and the horizontal drive motor 86 is mounted on theback of an end part of the rail part 84. The output shaft of the armraising/lowering motor 82 is connected to the arms 81, 81 by a feedmechanism made up of a feed screw and a nut. The output shaft of thehorizontal drive motor 86 is connected to the moving body 85 by a feedmechanism made up of a feed screw and a nut.

Next, the operation of the MEA carrying apparatus 72 described abovewill be explained, with reference to FIG. 10.

After trimming of an MEA 65 a (see FIG. 8) with the MEA trimmingapparatus 71 is finished, the carbon electrode 12 of the MEA 65 issuction-gripped by the first upper die suction-gripping part 44 and thePEM 13 is suction-gripped by the second upper die suction-gripping parts45. That is, with the MEA 65 suction-gripped, the arm raising/loweringmotor 82 is operated and along with the arms 81, 81 thesuction-gripping/holding device 17 and the upper trimming die 16 areraised as shown by the white arrow h.

Next, the horizontal drive motor 86 is operated, and by means of theslider 78 the post 79, the arms 81, 81, the suction-gripping/holdingdevice 17 and the upper trimming die 16 are moved horizontally as shownby the white arrows j and k.

After that, when the suction-gripping/holding device 17 and the uppertrimming die 16 have been moved to above the stacking part 73, the armraising/lowering motor 82 is operated, and along with the arms 81, 81the suction-gripping/holding device 17 and the upper trimming die 16 arelowered as shown by the white arrow m; the MEA 65 is set on a separator91 having been set on the stacking table 93; the suction-gripping of theMEA 65 by the first upper die suction-gripping part 44 and the secondupper die suction-gripping parts 45 is ceased; and the MEA 65 is therebystacked on the separator 91.

In this way, a cell is made from two separators 91 (one separator 91 isnot shown in the figure), and multiple cells are stacked to make a fuelcell battery.

As shown in FIG. 8, because the MEA carrying apparatus 72 has thesuction-gripping/holding device 17, if the MEA 65 (or the MEA 65 a) issuction-gripped by the suction-gripping/holding device 17 from the timeof trimming to the time of carrying, the MEA 65 can be carried from theMEA trimming apparatus 71, which is a trimming station, to the stackingpart 73, which is a stacking station, still in the state of the time oftrimming, without slipping sideways, and deviation of the stackingposition of the MEA 65 on stacking of the MEA 65 with the separator 91by the stacking part 73 can be prevented.

Consequently, when the MEA 65 is stacked, there is no need for theposition of the MEA 65 to be corrected, and a smooth transition can bemade from the carrying step to the stacking step. As a result, themanufacturability of the fuel cell can be improved.

As shown in FIG. 8, as a result of the MEA carrying apparatus 72 havingthe vertical movement mechanism 87 and the slider 78 serving as ahorizontal moving mechanism, there are two movement directions, andconsequently the direction of the force acting on the MEA 65 can be madea fixed direction at all times; it can be made difficult for shocks toact on the MEA 65 being carried; and sideways slipping of the MEA incarriage can be prevented. Therefore, when the MEA 65 is stacked, it isnot necessary for the position of the MEA 65 to be corrected, and asmooth transition can be made from the carrying step to the stackingstep.

Because, as described above, the fuel cell manufacturing apparatus 70has integrally the MEA trimming apparatus 71 constituting a trimmingstation, the MEA carrying apparatus 72 and the stacking part 73constituting a stacking station, a trimming step, a carrying step and astacking step can be carried out smoothly in a single series ofoperations, and the manufacture of a fuel cell can be carried outefficiently. Therefore, the productivity of the fuel cell can be raised,the manufacturing cost of the fuel cell can be reduced, and acontribution can be made to the spread for example of vehicles poweredby electric motors driven by fuel cells and of home generator systems.

The mechanism for suspending the pressing member on the upper trimmingdie may alternatively be constructed with a link mechanism providedbetween the two members and an elastic member for urging the pressingmember toward the lower trimming die.

Besides resin, the material of the nonmetallic plate in this embodimentmay alternatively be rubber, glass, ceramic or stone.

Although in this embodiment a porous plate was fitted on the bottom faceof the recess, the invention is not limited to this, and instead of aporous plate a recess-shaped air reservoir may be provided on thesuction-gripping means side face of a resin plate member, multiple smallholes provided passing through from this air reservoir to the electrodeside face, and this resin plate member attached to the bottom face ofthe recess in the upper trimming die.

And although in this embodiment dimensional error and assembly error ofthe various parts of the MEA trimming apparatus at the time of PEMtrimming were absorbed using a first bearing member and a second bearingmember, the invention is not limited to this, and alternatively thetrimming blade 15 may be attached to the upper trimming die 16 by way ofa free joint such as a ball joint, or the trimming blade 15 may beattached to the upper trimming die 16 by way of an elastic member or asoft member, to absorb these errors.

Also, although in this embodiment the MEA was moved from the trimmingstation to the stacking station by an MEA carrying apparatus, theinvention is not limited to this, and alternatively it may be made astructure wherein the lower trimming die of the MEA trimming apparatusand the stacking part are constructed so that they can move in astraight line on a horizontal movement mechanism and after trimming ofthe MEA the MEA is suction-gripped by suction-gripping/holding means andlifted with a vertical movement mechanism and the lower trimming die ismoved from under the MEA to elsewhere and the stacking part is moved todirectly under the MEA and the MEA which was being suction-gripped bythe suction-gripping/holding means is lowered with the vertical movementmechanism to stack a separator and the MEA.

When this construction is adopted, because the suction-gripping/holdingmeans suction-gripping the MEA is only moved in the vertical direction,the movement direction can be made a single direction and positionaldeviation of the MEA can be still better prevented.

INDUSTRIAL APPLICABILITY

In this invention, a membrane/electrode assembly trimming apparatus ismade up of a lower trimming die on which a membrane/electrode assemblyis placed, an upper trimming die having a trimming blade, and a pressingmember which is ascend/descendably suspended from this upper trimmingdie and suction-holds a carbon electrode, and a carrying apparatus isprovided with suction-gripping/holding means for suction-gripping thecarbon electrode and holding it so that it does not slip sideways. Withthis construction, because the certainty of positioning, fixing andtrimming at the time of trimming of the fuel cell membrane/electrodeassembly increases and positional slipping during carrying of thetrimmed membrane/electrode assembly can be prevented, the performance ofthe fuel cell improves. With this construction, a trimming step and acarrying step can be made to connect smoothly and the transition fromthe carrying step to a stacking step can be made smooth, andconsequently the productivity of the fuel cell increases. Accordingly,this invention is useful in the production of fuel cells used forelectric motors in vehicles and home generator systems.

1. A fuel cell membrane/electrode assembly trimming method for, with amembrane/electrode assembly made by affixing to both sides of a polymerelectrolyte membrane carbon electrodes of smaller area than this as theobject of trimming, trimming with a trimming blade the edge of thepolymer electrolyte membrane, characterized in that a recess with itsbottom face made of a nonmetallic plate is provided in the lowertrimming die, and after a carbon electrode is received in this recessand positioning of this carbon electrode is effected with two adjacentside walls of the recess the edge of the polymer electrolyte membrane issuction-gripped to the lower trimming die and the polymer electrolytemembrane is trimmed with the trimming blade.
 2. A fuel cellmembrane/electrode assembly trimming method according to claim 1,characterized in that the suction-gripping of the polymer electrolytemembrane is carried out on a part which becomes unneeded after trimmingof the polymer electrolyte membrane.
 3. A fuel cell membrane/electrodeassembly trimming apparatus for, with a membrane/electrode assembly madeby affixing to both sides of a polymer electrolyte membrane carbonelectrodes of smaller area than this as the object of trimming, trimmingwith a trimming blade the edge of the polymer electrolyte membrane,characterized in that it comprises a lower trimming die on which amembrane/electrode assembly is set and an upper trimming die having atrimming blade and a pressing member ascend/descendably suspended fromthis upper trimming die, and the pressing member is provided withsuction-gripping means for suction-gripping and holding one of thecarbon electrodes.
 4. A fuel cell membrane/electrode assembly trimmingapparatus according to claim 3, characterized in that a pressing partfor pressing down the edge of the polymer electrolyte membrane and arecess for receiving one of the carbon electrodes are provided in thepressing member, and an electrode suction hole for suctioning the carbonelectrode is provided in the bottom face of this recess, and a membranesuction hole for suctioning the polymer electrolyte membrane is providedin the pressing part.
 5. A fuel cell membrane/electrode assemblytrimming apparatus according to claim 4, characterized in that a porousplate is fitted to the bottom face of the recess and the carbonelectrode is suction-gripped using this porous plate.
 6. A fuel cellmembrane/electrode assembly trimming apparatus according to claim 3,characterized in that the mechanism suspending the pressing member fromthe upper trimming die is made up of a guide rod running between the twomembers and an elastic member urging the pressing member toward thelower trimming die.
 7. A fuel cell membrane/electrode assembly trimmingapparatus according to claim 3, characterized in that by providing thelower trimming die with a first bearing member with a larger area thanthe membrane/electrode assembly and fitting a second bearing member forbearing the edge of the polymer electrolyte membrane to this firstbearing member, it is made a structure which transmits the trimmingforce of the trimming blade in the order of the edge of the polymerelectrolyte membrane, the second bearing member, the first bearingmember.
 8. A fuel cell membrane/electrode assembly trimming apparatusaccording to claim 7, characterized in that the first bearing member isan elastic body.
 9. A fuel cell membrane/electrode assembly trimmingapparatus according to claim 8, characterized in that the second bearingmember is a soft material harder than the first bearing member.
 10. Afuel cell membrane/electrode assembly trimming apparatus whereinedge-trimming of a membrane/electrode assembly made by affixing to bothsides of a polymer electrolyte membrane carbon electrodes of smallerarea than this is carried out at a trimming station and for stacking ofthis edge-trimmed membrane/electrode assembly the membrane/electrodeassembly is carried from the trimming station to a stacking station,characterized in that it comprises a slider which moves from thetrimming station to the stacking station, an arm extending from thisslider, an upper trimming die which is suspended from this arm and has atrimming blade for the trimming, arm moving means for moving the arm,and a pressing member attached to the upper trimming die forsuction-gripping one of the carbon electrodes and holding it so that itdoes not slip sideways.
 11. A membrane/electrode assembly according toclaim 10, characterized in that the arm moving means comprises avertical movement mechanism for moving the arm in the vertical directionand a horizontal movement mechanism for moving the arm horizontally andin a straight line.